Despite repeated failed efforts to find oil, the Cuban government has pledged to resume offshore drilling in the deep waters of the Florida Straits, raising concerns in the U.S. about the threat of environmental damage along Florida’s coastline.

After a trip to Havana, former Senator and Florida Gov. Bob Graham said that the Cuban government is working with energy companies from Angola and Brazil to drill exploratory wells next year along the U.S.-Cuban maritime border. In desperate need of hard currency, Cuban officials believe that the country has billions of dollars of oil reserves sitting below the surface of its waters — even as multiple attempts to source it have come up short or empty.

Graham, who visited Cuba as part of a delegation from the Council of Foreign Relations, a nonpartisan think tank, said that despite Cuban reassurances of high safety standards, any oil spill would cause havoc along the Florida Keys, South Florida's coral reefs and beachfronts.

"If there were a spill of any significant size, without question it would impact Florida," Graham told the Sun-Sentinel newspaper. “This is an inherently risky operation when you are drilling two or more miles under the ocean.”

Over the last decade, more than $700 billion have been spent on exploring Cuba's alleged oil reserves but to little avail, as all foreign companies have pulled out of the country. Repsol, a Spanish firm, used a floating rig to find oil in waters north of Havana, but not enough to warrant full-on drilling. Russia’s Zarubezhnef also hunted for oil without success in shallow waters closer to shore.

While the possibility of an oil spill amid the U.S.’s embargo on the communist country is cause of deep concern among environmentalists, Cuban officials have made it clear that they plan to continue their search. Geological surveys indicate that between 5 and 9 billion barrels of oil may lie in deep waters off Cuban shores.

The Cuban oil craze has drawn concern from the anti-Castro Cuban exile population living in the U.S. – especially in the area of South Florida.

"The (U.S.) administration must finally wake up and see the truth that an oil rich Castro regime is not in our interests," Florida Rep. Ileana Ros-Lehtinen said in a 2012 statement.

Some cited Cuban oil exploration to argue for strengthening the embargo, which bans U.S. companies from doing business with Cuba and threatens sanctions against foreign firms if they don't play by its rules.

Others said it demonstrated the opposite: a need to ease the embargo so U.S. companies could more smoothly participate in disaster-response to any spill.